#include "los_api_xmodem.h"
#include "los_bsp_uart.h"
#include "string.h"

#define SOH  0x01  
#define STX  0x02  
#define EOT  0x04  
#define ACK  0x06  
#define NAK  0x15  
#define CANX  0x18
#define CTRLZ 0x1A  

#define XMODEM_MAX_RETRY_COUNT   10

#define XMODEM_TX_BUF_LEN  133   //SOH + ucPacketNumber + (~ucPacketNumber) + data(128byte) + checksum(1byte or 2bytes)
#define XMODEM_PACKET_DATA_LEN   128   //data(128byte)

static int last_error = 0;  

unsigned char LOS_PortIn_Byte(void)
{
    char ch;
    
    LOS_xModemHalPortInByte(&ch);
    
    return ch;
}

void LOS_PortOut_Byte(unsigned char ch)
{
    LOS_xModemHalPortOutByte(ch);
}

/**
  * @brief  XMODEM TRANSMIT
  * @param  unsigned char *src: data ptr
  *         int srcsz: data size
  * @retval > 0: transmit success
  *         = 0: transmit fail (termination)
  *         < 0: transmit fail (error)
  */
int LOS_xModemTransmit(unsigned char *src, int srcsz)
{  
    unsigned char ucTxBuf[XMODEM_TX_BUF_LEN];
    int bufsz, crc = -1;
    unsigned char ucPacketNumber = 1;
    int i, c, len = 0;
    int retry;
  
    for (;;)
    {
        for (retry = 0; retry < XMODEM_MAX_RETRY_COUNT; retry ++)
        {
            c = LOS_PortIn_Byte();
            if (last_error == 0)  //no error
            {
                switch (c)
                {
                case 'C':
                    crc = 1;
                    goto start_trans;
                case NAK:
                    crc = 0;
                    goto start_trans;
                case CANX:
                    break;
                default:
                    break;
                }
            }
        }
        return -1;

        for (retry = 0; retry < XMODEM_MAX_RETRY_COUNT; retry ++)
        {  
start_trans:
            bufsz = XMODEM_PACKET_DATA_LEN;
            ucTxBuf[0] = SOH;
            ucTxBuf[1] = ucPacketNumber;
            ucTxBuf[2] = ~ucPacketNumber;
            c = srcsz - len;
            if (c > bufsz)
                c = bufsz;
            if (c >= 0)
            {
                memset (&ucTxBuf[3], 0, bufsz);
                if (c == 0)
                {
                    ucTxBuf[3] = CTRLZ;
                }
                else
                {
                    memcpy (&ucTxBuf[3], &src[len], c);
                    if (c < bufsz)
                    {
                        int i;
                        for (i = 3 + c; i < (3 + XMODEM_PACKET_DATA_LEN); i ++)
                            ucTxBuf[i] = CTRLZ;
                    }
                }
                if (crc)
                {
                    unsigned short ccrc = LOS_xModemCRC16(&ucTxBuf[3], bufsz);
                    ucTxBuf[bufsz + 3] = (ccrc >> 8) & 0xFF;
                    ucTxBuf[bufsz + 4] = ccrc & 0xFF;
                }
                else
                {
                    unsigned char ccks = 0;
                    for (i = 3; i < bufsz + 3; i ++)
                    {
                        ccks += ucTxBuf[i];
                    }
                    ucTxBuf[bufsz + 3] = ccks;
                }
                
                for (retry = 0; retry < XMODEM_MAX_RETRY_COUNT; retry ++)
                {
                    //transmit one packet to PC
                    for (i = 0; i < bufsz + 4 + (crc ? 1 : 0); i ++)
                    {
                        LOS_PortOut_Byte(ucTxBuf[i]);
                    }
                    
                    c = LOS_PortIn_Byte();   //receive packet response from PC
                    if (last_error == 0 )
                    {
                        switch (c)
                        {
                        case ACK:
                            ucPacketNumber ++;
                            len += bufsz;
                            goto start_trans;   //transmit next packet to PC
                            break;
                        case CANX:   //transmit termination
                            return 0;
                            break;
                        case NAK:   //transmit last packet again
                            break;
                        default:
                            break;
                        }
                    }
                }
                return -2;
            }
            else   //transmit end
            {
                for (retry = 0; retry < XMODEM_MAX_RETRY_COUNT; retry ++)
                {
                    LOS_PortOut_Byte(EOT);    //MCU send EOT to request end of transmission
                    c = LOS_PortIn_Byte();
                    if (c == ACK)
                        break;
                }
                return (c == ACK) ? len : -3;
            }
        }
    }
    
    return -4;
}

/****************************** LOS_xModem CRC 16 START ******************************/
static const unsigned short crc16tab[256]= {
 0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,
 0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef,
 0x1231,0x0210,0x3273,0x2252,0x52b5,0x4294,0x72f7,0x62d6,
 0x9339,0x8318,0xb37b,0xa35a,0xd3bd,0xc39c,0xf3ff,0xe3de,
 0x2462,0x3443,0x0420,0x1401,0x64e6,0x74c7,0x44a4,0x5485,
 0xa56a,0xb54b,0x8528,0x9509,0xe5ee,0xf5cf,0xc5ac,0xd58d,
 0x3653,0x2672,0x1611,0x0630,0x76d7,0x66f6,0x5695,0x46b4,
 0xb75b,0xa77a,0x9719,0x8738,0xf7df,0xe7fe,0xd79d,0xc7bc,
 0x48c4,0x58e5,0x6886,0x78a7,0x0840,0x1861,0x2802,0x3823,
 0xc9cc,0xd9ed,0xe98e,0xf9af,0x8948,0x9969,0xa90a,0xb92b,
 0x5af5,0x4ad4,0x7ab7,0x6a96,0x1a71,0x0a50,0x3a33,0x2a12,
 0xdbfd,0xcbdc,0xfbbf,0xeb9e,0x9b79,0x8b58,0xbb3b,0xab1a,
 0x6ca6,0x7c87,0x4ce4,0x5cc5,0x2c22,0x3c03,0x0c60,0x1c41,
 0xedae,0xfd8f,0xcdec,0xddcd,0xad2a,0xbd0b,0x8d68,0x9d49,
 0x7e97,0x6eb6,0x5ed5,0x4ef4,0x3e13,0x2e32,0x1e51,0x0e70,
 0xff9f,0xefbe,0xdfdd,0xcffc,0xbf1b,0xaf3a,0x9f59,0x8f78,
 0x9188,0x81a9,0xb1ca,0xa1eb,0xd10c,0xc12d,0xf14e,0xe16f,
 0x1080,0x00a1,0x30c2,0x20e3,0x5004,0x4025,0x7046,0x6067,
 0x83b9,0x9398,0xa3fb,0xb3da,0xc33d,0xd31c,0xe37f,0xf35e,
 0x02b1,0x1290,0x22f3,0x32d2,0x4235,0x5214,0x6277,0x7256,
 0xb5ea,0xa5cb,0x95a8,0x8589,0xf56e,0xe54f,0xd52c,0xc50d,
 0x34e2,0x24c3,0x14a0,0x0481,0x7466,0x6447,0x5424,0x4405,
 0xa7db,0xb7fa,0x8799,0x97b8,0xe75f,0xf77e,0xc71d,0xd73c,
 0x26d3,0x36f2,0x0691,0x16b0,0x6657,0x7676,0x4615,0x5634,
 0xd94c,0xc96d,0xf90e,0xe92f,0x99c8,0x89e9,0xb98a,0xa9ab,
 0x5844,0x4865,0x7806,0x6827,0x18c0,0x08e1,0x3882,0x28a3,
 0xcb7d,0xdb5c,0xeb3f,0xfb1e,0x8bf9,0x9bd8,0xabbb,0xbb9a,
 0x4a75,0x5a54,0x6a37,0x7a16,0x0af1,0x1ad0,0x2ab3,0x3a92,
 0xfd2e,0xed0f,0xdd6c,0xcd4d,0xbdaa,0xad8b,0x9de8,0x8dc9,
 0x7c26,0x6c07,0x5c64,0x4c45,0x3ca2,0x2c83,0x1ce0,0x0cc1,
 0xef1f,0xff3e,0xcf5d,0xdf7c,0xaf9b,0xbfba,0x8fd9,0x9ff8,
 0x6e17,0x7e36,0x4e55,0x5e74,0x2e93,0x3eb2,0x0ed1,0x1ef0
};

unsigned short LOS_xModemCRC16(const unsigned char *buf, int len)
{
    register int counter;
    register unsigned short crc = 0;
    
    for (counter = 0; counter < len; counter ++)
    {
        crc = (crc << 8) ^ crc16tab[((crc >> 8) ^ *(char *)buf ++) & 0x00FF];
    }
    
    return crc;
}
/****************************** LOS_API_xModem CRC 16 END ******************************/

